Many electronic devices, especially semiconductor chips, such as a central processing unit (CPU) chip, for example Intel 80486 (registered mark of Intel Co.) chip, operate in a limited temperature range, and they usually malfunction when the temperature is outside the range. On the other hand, electronic devices generate heat during operation. To maintain proper operation temperature, the heat generated during the operation of the electronic devices must be removed or dissipated.
Heat sink apparatus have been already known for removal or dissipation of thermal energy from electronic devices. Examples of such heat sink apparatus are U.S. Pat. Nos. 4,879,891, 4884,331 and 4,745,456, UK patent No. 2,195,051 which is a counterpart of U.S. Pat. No. 4,745,456, and Chinese patent No. 93 2 22472.5 which all disclose a heat sink having a body to be secured to a surface of a heat generating electronic device in a thermal contact manner and a plurality of spaced heat dissipating fins or pins extending from the body to dissipate thermal energy generated by the electronic device to the environment. These prior art heat sink apparatus dissipate heat by natural convection occurring between the fins or pins that are heated by the thermal energy generated by the electronic device and the low temperature environmental air.
Due to the development of high power semiconductor devices, the amount of thermal energy to be removed from semiconductor devices increases and natural convection may no longer be sufficient for properly removing heat from the electronic devices. To increase the heat removal efficiency, heat sink apparatus is improved by incorporating a fan to cause air flow to performing forced convection, which fan is generally disposed on the top of the fins to generate the required air flow through the fins of the heat sink apparatus for force convection. Examples of the forced convection type heat sink apparatus for IC chip are Taiwan Patent Application Nos. 83204206 and 83212398 and U.S. patent Ser. No. 08/257,106, all filed by the applicant of the present invention.
The prior art forced convection type heat sink apparatus, although working well in removing heat, require separate or additional fasteners, such as screws, to secure them together. This complicates the assembly of the heat sink apparatus and increases the overall cost.
It is therefore desirable to provide a forced convection type heat sink apparatus which overcomes the deficiencies of the prior art heat sink apparatus.